Pulverizing apparatus



- NOV. 1 A. c. BEARDSIJEE EI'AL 2,261,209

PULVERIZING APPARATUS Filed Nov. 19, 1957 3 SheetsSheet l INVENTOR CHARLES 6. CLARK BY A/PTHl/l? QBHRDSLEE ATTORNEY v Nov. 4, 1941. A. c. BEARDSLEE ET AL 2,261,209-

PULVERIZING APPARATUS I Filed Nov. 19, 1957 3 Sheets-Sheet 2' INVENTOR CHARLfS G. CZ/IRK BY A/iT/vll/f czmwm A-TTORNE-Y Nov. 4, 1941. A. c. BEARDSLEE ET Al:

' PULVERIZING APPARATUS FiledfNov. 19, 193? :5 Sheets-Sheet s I INVENTOR CHARLES z CL -Aemu/e c. zmosu ATTORNEY Patented Nov. 4, 1941 PULVERIZING APPARATUS Arthur C. Beardslee and Charles G.

Clark,

Arcade, N. Y., assignors to The Borden Com- Y., a corporation of New pany, New York, N.

Jersey Application November 19, 1937, Serial No. 175,374

Claims.

This invention relates to apparatus for pulverizing solid materials, such as dried milk products, which might be damaged by frictional heat.

Most pulverizing apparatus relies on the use of contact members to effect a cutting, grinding or abrasive action on the material to be pulverized. Heat destructible solids such as dried milk solids, casein, whey, or the like, frequently can be improved by further comminution but are seriously damaged if pulverized in the usual apparatus where considerable frictional heat is generated. In addition, such apparatus would usually beclogged by the treatment of products of this type.

It is an object of this invention to provide apparatus for pulverizing heat destructible solids to a 'flne'state in an eflicient manner without damage to such products.

Another object is the provision of pulverizing apparatus for heat destructible solids without damage thereto in which the capacity of the apparatus is increased for a given expenditure of power. i

A further object of our invention is to provide a high speed centrifugal pulverizer of high capacity wherein the solids are moved at high velocity over and through a foraminous member, and admixed with heated air after passing through said member.

The invention will be more particularly described in connection with the embodiment thereof illustrated in the drawings, in which- Figure 1 is a longitudinal vertical sectional view of pulverizing apparatus in accordance with our invention. Figure 2 is a vertical sectional view through the first chamber of the apparatus and taken on the offset line 22 of Figure l.

, Figure 3 is a vertical sectional view through the second chamber of theapparatus and taken on the line 3-3 of Figure 1.

tatably mounted in bearing housings i3 and 23.

and extends through the casings II, M and 2|. Suitable ball bearings 28 for shaft 26 may be provided in the-housing I3 and ball bearings 29 may also be employed in the housing 2". Lubricant such as grease may be retained in the bear- Figure 4 is a vertical sectional view taken through thefeed hopper of the apparatus on the line 4- -4 of Figure 1.

With reference to the drawings, the pulverizer housing includes a frame It supporting a circular casing At one side, the casing II is provided with an integral bearing housing I3 and reinforcing flanges Ila; at the other side, casing II has a circular opening l2. The bearing housing I3 and flange ||a are preferably, arranged eccentric to the circular casing H which has an integral tangential outlet |2a. Connected to casing next to the opening I2, is an annular casing member |4 provided with a central opening l5 which communicates with opening i2, radially disposed webs l6 integral with the discshaped partition I1, and the annular ring l8. Integral with the casing member I4 is a circular shell IS. The annular casing member I4 with 6 the radius 01' the shaft 26. The blades may be 1 ing housings by grease retaining discs30. Felt washers 30a also serveto retain lubricant and to cushion any axial thrust of. the shaft 26. Shaft 26 may also be threaded near one end to receive nut 306 which together with collar 30c and shoulder 30d provides for adjustment of the end play of shaft 26, Fixed to shaft 26 in the trough portion 24 of easing member 2| is a helical feed screw 3| fixed to the shaft by aset screw 32.

Between partition i1 and the annular ring l8 an impeller 33 may be fixed to the shaft by the set screw 34. This impeller preferably comprises a hub portion 35' having an integral radially extending flange 36 which carries a series of impeller blades 31. The other ends of the impeller blades 31 may be fixed to the freely rotating annular disc 38. These impeller blades 31 are preferably relatively narrow and inclined rearwardly at a small angle with respect to a radius from the shaft 26. Radial flange 33 is preferably spaced 8. small distance from partition l1 and provided with integral fins 36a to prevent accumulation of material in said space. The impeller blades are also preferably closely addacent to but not in'contact with a circular screen 39 which may be formed of arcuate sections. These sections are clamped atone end between the annular ring l8 and the two semi-circular rings 40, having flanges 4| held between the ring I8 and the casing 2| by the bolts 20. At their other end, the screen sections are preferably supported on two semi-circular ring sections 42, said ring sections 42 being supported in notches (not shown) in the radial webs l6. Screen sections 39 are held rigidly in place and prevented from bulging outwardly by a pair of annular bands 43.

Inside the casing II, a. rotor 44 is fixed to shaft 26 by 'set screw 45. This rotor 44 may be constructed similar to impeller 33 with a radial flange 46- at one end, but carrying a plurality of blades 41 inclined forwardly with respect to held in fixed relation to each other at their other ends by an annular ring 43.

The material to be pulverized maybe introduced through a'screen 49a in hopper 22 whence it is moved axially of shaft 26 by conveyor 3! erably provided around this opening' 49' commun-' icating with a supply conduit ii and containing a suitable screen 52. Air may thus be' supplied to the pulverizer through conduit 51, screen 52, and casing 50 where it sweeps over screen 39 and mingles with the pulverized material coming out through screen 39, thereafter passing in the direction of the arrows through the opening 15 to the rotor 44. The blades 41 of rotor 44 preferably extend a greater distance from shaft 26 than the impeller blades 31 to create a suction for assisting in the removal of material from screen 39? The blower or rotor 44 is also preferably arranged eccentrically with respect to the casing l I so that the greatest space between the impeller blades 41 and the casing il occurs near the outlet i2a. Pulverized material may be discharged through the outlet l2a to a suitable dust collector or other device for separating solid material from the air. Heated air is preferably introduced through conduit when material such as dried milk is beingpulverized to provide a drying effect and also to prevent the pulverized solids from clogging screen 39.

The apparatus is preferably operated at high speeds of the order of 3600 R. P. M. to accomplish the pulverizing action and is particularly useful for pulverizing roller dried milk powder. In the operation. of the apparatus, material to be pulverized, such as roller dried milk powder is introduced into the hopper 22 through screen 49a and is conveyed by the helical screw 3i through opening 25 into the path of impeller 33. Blades 31 rapidly rotate the solid material throwing it outwardly by centrifugal force through the screen 39 and moving it over the inner surface of said screen 39. The fineness of the material may be varied by using screens of different mesh. Usual woven wire screens have been found to be suitable for this purpose.

Drying air, heated for example to a temperature of about 195 F. for roller dried milk, is introduced throughconduit 5i and annular opening 49 to sweep over the outer surface of screen 39 in the direction of the arrows and exert a drying action on the freshly pulverized milk solids. The mixture of heated air and pulverized material then passes through the cylindrical casing member [9 and the opening i5 into the path of the rotor 44 where the pulverizing action is completed before the material is discharged through outlet i2a.

Little, if any air is mixed with the material fed through opening 25, thereby increasingthe capacity of the impeller 33. By introducing warm air through conduit 5|, the screen 39, the rotor 44, and the casing II are maintained relatively free from any coating of pulverized material which might impair the operation of the apparatus. In addition, the ultimate pulverized product has a lower moisture content than would otherwise be obtained.

By subjecting materials, such as roller dried milk powder, first to the pulverization by attritionof the impeller 33 and screen 39 and thereafter mixed with warm air to the pulverization by impact of the rotor 44 in casing Ii, it has been found that the best, results are obtained.

The terms and expressions which we have employed are used as terms of description and not of limitation, and we have no intention, in

that various modifications are possible within I the scope of the invention as claimed.

We claim:

1. Apparatus of the character described comprising a casing, an impeller arranged for rotation within said casing,a foraminous member in said casing surrounding and spaced from said impeller, means for feeding material to be pulverized into said impeller so that said material is forced through said member, and means for supplying and directing a current of air independent of any air passing through said member over substantially the entire outer surface of said member in a direction axially of said impeller.

2. A high speed centrifugal pulverizer comprising a casing, a rotary impeller within said casin having fixed blades disposed for movement in a direction approximately normal to their planes, a foraminous member surrounding and spaced from said impeller, a rotor comprising blades similar to the blades of said impeller, means for feeding material to be pulverized to said impeller,

and means for conducting pulverized material passed through said member to said rotor, the blades of said impeller and of said rotor being inclined rearwardly and forwardly, respectively.

3. A high speed centrifugal pulverizer comprising a casing, a rotary impeller within said casing having blades for forcing material outwardly by centrifugal force, a shaft for rotating said impeller, a stationary screen surrounding said blades, a hopper associated with said casing. means for feeding material from the lower por-- tion of said hopper along saidshaft into the impeller, and means for supplying a current of drying air to the outer surface of said screen.

4. Apparatus of the character described comprising a casing, a shaft extending into said casing, an impeller having flat blades fixed to said shaft for rotation within said casing, a 'foraminous member in said casing surrounding and spaced from said impeller blades, a feed screw on said shaft for feeding material to be pulverized into a central portion of said impeller, and means for supplying a current of air to said material only after it has passed through said foraminous member.

5. A high speed centrifugal pulverizer comprising a casing, a shaft extending through said casing, a rotary impeller within said casing having blades fixed to said shaft for movement in a direction approximately normal to their planes, a foraminous member surrounding said impeller, a rotor comprising blades fixed to said shaft similar to said impeller blades, means fixed to said shaft for feeding material to be pulverized to a central portion of said impeller, means for conducting material passed through said foraminous member to a central portion of said rotor, and means for introducing a current of heated air into the material in said conducting means.

ARTHUR C. BEARDSLEE. CHARLES G, CLARK. 

